[Angioarchitecture and Associated Dural Arteriovenous Fistulas of the Superior Petrosal Sinus and Petrosal Vein].

The superior petrosal sinus and petrosal vein are important drainage routes for the posterior cranial fossa, with some variations and collateral vessels. An anterolateral-type tentorial dural arteriovenous fistula, which occurs around the petrosal vein, often develops aggressive symptoms due to venous reflux to the brainstem and cerebellum. Neuroendovascular treatment of this fistula is usually challenging because transarterial embolization has a high risk and indications for transvenous embolization are limited. In the cavernous sinus and transverse sinus/sigmoid sinus dural arteriovenous fistulas, venous reflux to the petrosal vein is dangerous, and a treatment strategy with the occlusion of the petrosal vein is indispensable. Furthermore, attention should be paid to venous approaches through the superior petrosal sinus.

[Preoperative Simulation of Neuroendovascular Therapy Using a Three-Dimensional Printer Model of a Tailor-Made Hollow Cerebral Aneurysm].

Several studies have reported the importance of preoperative simulations. This report describes the methods and utility of neuroendovascular treatment using a three-dimensional(3D)-printed hollow cerebral aneurysm model. This model was created using a stereolithography apparatus-type 3D printer with digital imaging and communications in medicine data from 3D digital subtraction angiograms. The 3D model was used to perform preoperative simulations of microcatheter placement in aneurysms, microguidewire manipulation, and stent deployment. We performed each simulated procedure during surgery. The hollow cerebral aneurysm 3D model can also be used as a training model for surgical trainees. Preoperative simulation using a high-precision hollow cerebral aneurysm model created using 3D printers enables the discussion of specific treatment strategies for each case, including new devices and device sizes, and is expected to develop into "tailor-made medicine" in the future, contributing to safe and reliable treatment implementation.

Mobile endovascular therapy for acute treatment of ruptured vertebral artery dissecting aneurysm in multiple hospitals.

BACKGROUND: The patients with ruptured vertebral artery dissecting aneurysm (rVADA) should be treated as early as possible because VADA carries extremely high risk of rebleeding in the acute phase. We have established a mobile endovascular strategy for the patients with rVADA between our flagship center and its affiliated local hospitals. We introduced and reviewed our mobile endovascular therapy in this study. METHODS: We retrospectively evaluated 98 consecutive patients who underwent endovascular surgery for rVADA from 2000 to 2018 at our institution or five affiliated hospitals. When each patient was initially transported to the local affiliated hospitals, neuroendovascular surgeons traveled directly to the affiliated hospital from the flagship center in order to treat the patient there. Clinical outcomes using modified Rankin Scale at 6 months after treatment, radiological results, and procedure-related complications were reviewed to justify our mobile endovascular strategy. RESULTS: All aneurysms were cured successfully by internal trapping. Favorable outcome was achieved in 61 patients (62.2%) even though 53 patients (54.1%) had presented with severe subarachnoid hemorrhage. Overall mortality rate, treatment-related mortality rate, and treatment related complication rate were 18.4% (18/98), 0%, and 16% (16/98), respectively. There were no differences in clinical and radiological outcomes between the patients treated in the flagship center and those who treated in the affiliated hospitals. Treatment in the affiliated hospital was not a predictive factor of unfavorable outcome in our multivariate analysis, and elderly age (≥ 60) was negatively associated with favorable outcome. CONCLUSIONS: Our results prove the efficacy and safety of mobile endovascular therapy for the treatment of rVADA in the ultra-acute stage. Mobile endovascular therapy may work well in the acute treatment of rVADAs in the certain circumstance.

A case of delayed foreshortening and disconnection of pipeline embolization device detected by chronological cone-beam computed tomography fusion image.

OBJECTIVE: The morphological changes of the pipeline embolization device (PED; Medtronic, Minneapolis, MN, USA), such as delayed migration or foreshortening, can relate to the incomplete occlusion of aneurysms. CASE PRESENTATION: A 30-year-old man with a giant cavernous carotid artery aneurysm was treated with two PEDs using the overlapping technique. Six months after treatment, follow-up angiography showed morphological changes of the PEDs and residual flow into the aneurysm. Chronological cone-beam computed tomography fusion imaging clearly revealed the dynamic foreshortening of the first PED and the disconnection of both PEDs, so we decided to implant an additional PED. CONCLUSION: This case illustrates that a three-dimensional understanding can be useful for assessing the cause of treatment failure or recurrence.

Treatment outcome of coil embolization for distal anterior cerebral artery aneurysms: A single-center experience.

OBJECTIVE: In recent years, endovascular treatment has become the treatment of choice for distal anterior cerebral artery (DACA) aneurysms. In this study, we report the outcomes of coil embolization for DACA aneurysms. METHODS: Eighteen DACA aneurysms in 16 patients treated with endovascular treatment between January 2010 and December 2020 were included in this study. We retrospectively analyzed patient characteristics, data on aneurysms, the reason for the selection of endovascular treatment, treatment technique, and treatment outcomes. RESULTS: There were 18 procedures in 16 patients. The average age was 65.7 years and 56% of patients were male. The average diameter of the dome was 5.5 mm, and the location of aneurysm was A3 in 83% and A4 in 17%. We mainly selected endovascular treatment for patients with a past history of craniotomy and head trauma, or with systemic comorbidities. The technical success rate was 94%, and adequate obliteration immediately after treatment was achieved in 72%. There were no symptomatic periprocedural complications. The retreatment rate was 11.1%. CONCLUSION: Coil embolization for DACA aneurysms yielded good treatment outcomes. Endovascular treatment for DACA aneurysms will become more common with advances in endovascular devices and the establishment of stable perioperative antiplatelet therapy.

[Visualization of Cerebrospinal Micro-Angioarchitecture].

Researchers have been trying to visualize fine angioarchitecture in cerebrospinal vascular lesions and the positional relationship between vascular lesions and surrounding structures. The aim of this article was to introduce the usefulness of imaging in visualizing the microvascular anatomy in cerebrospinal vascular lesions, such as aneurysm, arterial dissection, arteriovenous malformation, dural arteriovenous fistula(AVF), spinal dural and epidural AVF, and craniocervical junction AVF. For the imaging modality, we used high-resolution magnetic resonance imaging, three-dimensional rotational angiography(3D-RA), slab maximum intensity projection image from 3D-RA, cone-beam computed tomography, and fusion imaging. If fully exploited, imaging can contribute to clinical analysis and surgical treatment and be an essential tool for achieving maximum therapeutic effect without complications.

[Neuroendovascular Therapy and Infection].

In this paper, we will discuss the relationship between neuroendovascular therapy and infection in two parts: the risk of infectious complications in neuroendovascular therapy and neuroendovascular therapy for infectious diseases. The risk of infectious complications associated with neuroendovascular therapy is rare but should not be ignored. We must comply with clean procedures and consider prophylactic antibiotic administration in selected cases. Neuroendovascular therapy for infectious diseases is a high-risk treatment, and a safer treatment strategy should be considered for each case.

Trends in Incidence of Intracranial and Spinal Arteriovenous Shunts: Hospital-Based Surveillance in Okayama, Japan.

BACKGROUND AND PURPOSE: To date, the incidence of intracranial and spinal arteriovenous shunts has not been thoroughly investigated. We aimed to clarify recent trends in the rates of intracranial and spinal arteriovenous shunts in Japan. METHODS: We conducted multicenter hospital-based surveillance at 8 core hospitals in Okayama Prefecture between April 1, 2009 and March 31, 2019. Patients who lived in Okayama and were diagnosed with cerebral arteriovenous malformations, dural arteriovenous fistulas (DAVFs), or spinal arteriovenous shunts (SAVSs) were enrolled. The incidence and temporal trends of each disease were calculated. RESULTS: Among a total of 393 cranial and spinal arteriovenous shunts, 201 (51.1%) cases of DAVF, 155 (39.4%) cases of cerebral arteriovenous malformation, and 34 (8.7%) cases of SAVS were identified. The crude incidence rates between 2009 and 2019 were 2.040 per 100 000 person-years for all arteriovenous shunts, 0.805 for cerebral arteriovenous malformation, 1.044 for DAVF, and 0.177 for SAVS. The incidence of all types tended to increase over the decade, with a notable increase in incidence starting in 2012. Even after adjusting for population aging, the incidence of nonaggressive DAVF increased 6.0-fold while that of SAVS increased 4.4-fold from 2010 to 2018. CONCLUSIONS: In contrast to previous studies, we found that the incidence of DAVF is higher than that of cerebral arteriovenous malformation. Even after adjusting for population aging, all of the disease types tended to increase in incidence over the last decade, with an especially prominent increase in SAVSs and nonaggressive DAVFs. Various factors including population aging may affect an increase in DAVF and SAVS.

Osseous arteriovenous fistulas in the dorsum sellae, clivus, and condyle.

PURPOSE: Arteriovenous fistulas (AVFs) located in the cavernous sinus (CS), clivus, and condyle can be osseous shunts in nature. Here, we reviewed the angioarchitecture, clinical characteristics, and treatment results of AVFs in these lesions. METHODS: Twenty-five patients with 27 lesions who underwent rotational angiography in our department between May 2013 and December 2019 were reviewed. We examined 20 CS AVFs, 2 clival AVFs, and 5 condylar AVFs. We divided the anatomical shunted pouches into five locations: the dorsum sellae (posteromedial of the CS), posterolateral wall of the CS, lateral wall of the CS, clivus, and condyle. We divided the AVFs into three categories: intraosseous, transitional, and nonosseous shunts. We analyzed the characteristics and treatment results. RESULTS: A total of 33 shunted pouches or points were identified in 27 lesions. The dorsum sellae (n = 16) was the most frequent location. Fourteen AVFs (88%) in the dorsum sellae were osseous (intraosseous or transitional) shunts. All AVFs in the clivus or condyle were also osseous shunts. Eleven lesions (92%) of intraosseous and all lesions of transitional shunts exhibited bilateral external carotid artery involvement as feeders. Ten lesions (83%) of intraosseous shunts were treated with selective transvenous embolization of the shunted pouch with or without additional partial embolization of the sinus. Eleven (92%) intraosseous shunts were completely occluded, and symptom resolution was achieved in all intraosseous shunts. CONCLUSION: Most of the CS AVFs with shunted pouches in the dorsum sellae and all of the AVFs in the clivus and condyle share similar characteristics.

[Intracerebral Hemorrhage].

CT angiography(CTA)plays a crucial role in the diagnosis of intracerebral hemorrhage(ICH). An 85-year-old woman presented with a disturbance of consciousness and right hemiparesis. Non-contrast CT of the brain revealed intracerebral hemorrhage in the left thalamus spreading to the internal capsule, corona radiata, and midbrain and a "swirl sign." CTA revealed no vascular anomaly. The early and delayed CTA phases revealed the"spot sign" and "leakage sign," respectively. Non-contrast CT three hours after the initial CT showed the enlargement of the hematoma. After the detection of ICH by initial non-contrast CT, CTA should be performed to differentiate between the causes of secondary ICH and detect the imaging markers of hematoma expansion or rebleeding. Previous studies have demonstrated that the "spot sign" detected by CTA is a valid imaging marker for hematoma expansion. In this article, the differential diagnosis of ICH and the detection of the imaging markers of hematoma expansion using non-contrast CT and CTA have been discussed.

Detection of the common origin of the radiculomedullary artery with the feeder of spinal dural arteriovenous fistula using slab maximum intensity projection image.

PURPOSE: Endovascular therapy to the spinal dural arteriovenous fistula (SDAVF) with a common origin of the radiculomedullary artery and the feeder of the shunt has the risk of spinal cord infarction. This study aimed to retrospectively assess the detection rate of normal spinal arteries from the feeder of SDAVF. METHODS: We retrospectively collected the angiographic and clinical data of SDAVFs. This study included 19 patients with 20 SDAVF lesions admitted to our department between January 2007 and December 2018. We assessed the detection rate of normal radiculomedullary artery branched from the feeder of SDAVF between the period using the image intensifier (II) and flat panel detector (FPD) and evaluated the treatment results. RESULTS: The detection rates of the radiculomedullary artery branched from the feeder of SDAVF were 10% (1/10 lesions) during the II period and 30% (3/10 lesions) during the FPD period. During the FPD period, all normal radiculomedullary arteries branched from the feeder were only detected on slab maximum intensity projection (MIP) images of rotational angiography, and we could not detect them in 2D or 3D digital subtraction angiography. All lesions that had a common origin of a normal radiculomedullary artery and the feeder were completely obliterated without complications. There was no recurrence during the follow-up period. CONCLUSIONS: The flat panel detector and slab MIP images seem to show the common origin of the normal radiculomedullary arteries from the feeder more accurately. With detailed analyses, SDAVF can be safety treated.

Safety and efficacy of staged angioplasty for patients at risk of hyperperfusion syndrome: a single-center retrospective study.

PURPOSE: Intracranial hemorrhage following hyperperfusion syndrome (HPS) is a rare but potentially fatal complication after carotid artery stenting (CAS). Staged angioplasty (SAP) is a two-stage form of CAS that can prevent the abrupt increase of cerebral blood flow. In this study, we investigated the safety and efficacy of SAP. METHODS: One hundred thirty-four patients who underwent CAS for high-grade carotid artery stenosis between January 2010 and December 2018 were enrolled. Patients who showed severe impairment of hemodynamic reserve in 123I-IMP SPECT with acetazolamide received SAP (SAP group), while the others received regular CAS (RS group). RESULTS: Twenty-six (19.4%) patients at risk for HPS received SAP. HPS was not observed in either group. Diffusion-weighted image (DWI)-positive lesions on postoperative MRI were observed in 56 (52.3%) cases in the RS group and 16 (64.0%) cases in the SAP group. Symptomatic procedure-related complications occurred in 5 (4.6%) cases in the RS group and 1 (3.8%) case in the SAP group. These differences were not statistically significant. Modified Rankin Scale score had declined 30 days after discharge in 4 (3.0%) cases. Distal filter protection was significantly correlated to the occurrence of new DWI-positive lesions. CONCLUSIONS: For patients at high risk of HPS, SAP was a reasonable treatment strategy to prevent HPS. SAP did not increase the rate of DWI-positive lesions or procedure-related complications compared with regular CAS.

Metal artifact reduction algorithm for image quality improvement of cone-beam CT images of medium or large cerebral aneurysms treated with stent-assisted coil embolization.

PURPOSE: The aim of the present study was to assess image quality improvement using a metal artifact reduction (MAR) algorithm in cases of medium or large cerebral aneurysms treated with stent-assisted coil embolization (SAC), and to analyze factors associated with the usefulness of the MAR algorithm. METHODS: We retrospectively evaluated the cone-beam computed tomography (CBCT) data sets of 18 patients with cerebral aneurysms treated with SAC. For subjective analysis, images of all cases with and without MAR processing were evaluated by five neurosurgeons based on four criteria using a five-point scale. For objective analysis, the CT values of all cases with and without MAR processing were calculated. In addition, we assessed factors associated with the usefulness of the MAR by analyzing the nine cases in which the median score for criterion 1 improved by more than two points. RESULTS: MAR processing improved the median scores for all four criteria in 17/18 cases (94.4%). Mean CT values of the region of interest at the site influenced by metal artifacts were significantly reduced after MAR processing. The maximum diameter of the coil mass (< 17 mm; odds ratio [OR], 4.0; 95% confidence interval [CI], 1.2-13.9; p = 0.02) and vessel length covered by metal artifacts (< 24 mm; OR, 2.3; 95% CI, 1.1-4.7; p = 0.03) was significantly associated with the usefulness of the MAR. CONCLUSIONS: This study suggests the feasibility of a MAR algorithm to improve the image quality of CBCT images in patients who have undergone SAC for medium or large aneurysms.

Cerebellar Blood Flow and Gene Expression in Crossed Cerebellar Diaschisis after Transient Middle Cerebral Artery Occlusion in Rats.

Crossed cerebellar diaschisis (CCD) is a state of hypoperfusion and hypometabolism in the contralesional cerebellar hemisphere caused by a supratentorial lesion, but its pathophysiology is not fully understood. We evaluated chronological changes in cerebellar blood flow (CbBF) and gene expressions in the cerebellum using a rat model of transient middle cerebral artery occlusion (MCAO). CbBF was analyzed at two and seven days after MCAO using single photon emission computed tomography (SPECT). DNA microarray analysis and western blotting of the cerebellar cortex were performed and apoptotic cells in the cerebellar cortex were stained. CbBF in the contralesional hemisphere was significantly decreased and this lateral imbalance recovered over one week. Gene set enrichment analysis revealed that a gene set for "oxidative phosphorylation" was significantly upregulated while fourteen other gene sets including "apoptosis", "hypoxia" and "reactive oxygen species" showed a tendency toward upregulation in the contralesional cerebellum. MCAO upregulated the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the contralesional cerebellar cortex. The number of apoptotic cells increased in the molecular layer of the contralesional cerebellum. Focal cerebral ischemia in our rat MCAO model caused CCD along with enhanced expression of genes related to oxidative stress and apoptosis.

[A Case of Ruptured Arteriovenous Malformation Successfully Treated with Target Embolization for Pseudoaneurysm Detected Using Chronological Three-dimensional Digital Subtraction Angiography Fusion Images].

We herein report a case of ruptured arterio-venous malformation(AVM)detected using three-dimensional digital subtraction angiography(3DDSA)fusion images and successfully treated with target embolization for pseudoaneurysm. A 50-year-old man with a history of AVM was admitted to our department for the treatment of ruptured high-grade AVM in the right parietal lobe. Although a bleeding point was not evident on DSA, the patient had re-rupture in the right ventricle, one month after admission. Chronological 3DDSA fusion images generated from 3DDSA images taken on admission and after re-rupture revealed a newly visualized intranidal pseudoaneurysm near a hematoma. Contrast-enhanced magnetic resonance imaging showed vessel wall enhancement along the posterior horn of the right ventricle;this enhancement corresponded to the location of the pseudoaneurysm. We planned target embolization for the intranidal pseudoaneurysm to prevent re-bleeding. The origin of the feeder was so steep that a microcatheter could not be advanced deeply, and embolization with 20% n-butyl-2-cyanoacrylate resulted in proximal occlusion. Follow-up angiography 1 week after embolization showed complete disappearance of the pseudoaneurysm, and the patient had no recurrence of aneurysm until one year.

Endovascular treatment for unruptured aneurysm associated with persistent primitive trigeminal artery: a case report and literature review.

The persistent primitive trigeminal artery (PPTA) is the most common carotid-basilar anastomosis, and the incidence of cerebral aneurysms associated with the PPTA is approximately 4%. Since PPTA aneurysms often have a wide neck and other vascular anomalies, endovascular treatment using an adjunctive technique is the current first-line therapy. Here, we report a case of PPTA aneurysm treated by coil embolization with a stent-assisted technique. A detailed evaluation of the size and course of all vessels and collateral flow, including the Allcock test and balloon test occlusion, is necessary when deciding on the treatment strategy.

A comparison of the prevalence and risk factors of complications in intracranial tumor embolization between the Japanese Registry of NeuroEndovascular Therapy 2 (JR-NET2) and JR-NET3.

BACKGROUND: The Japanese Registry of NeuroEndovascular Therapy 2 (JR-NET2) and 3 (JR-NET3) were nationwide surveys that evaluated clinical outcomes after neuroendovascular therapy in Japan. The aim of this study was to compare the prevalence and risk factors of complications of intracranial tumor embolization between JR-NET2 and JR-NET3. METHODS: A total of 1018 and 1545 consecutive patients with intracranial tumors treated with embolization were enrolled in JR-NET2 and JR-NET3, respectively. The prevalence of complications in intracranial tumor embolization and related risk factors were compared between JR-NET2 and JR-NET3. RESULTS: The prevalence of complications in JR-NET3 (3.69%) was significantly higher than that in JR-NET2 (1.48%) (p = 0.002). The multivariate analysis in JR-NET2 showed that embolization for tumors other than meningioma was the only significant risk factor for complication (odds ratio [OR], 3.88; 95% confidence interval [CI], 1.13-12.10; p = 0.032), and that in JR-NET3 revealed that embolization for feeders other than external carotid artery (ECA) (OR, 3.56; 95% CI, 2.03-6.25; p < 0.001) and use of liquid materials (OR, 2.65; 95% CI, 1.50-4.68; p < 0.001) were significant risks for complications. The frequency of embolization for feeders other than ECA in JR-NET3 (15.3%) was significantly higher than that in JR-NET2 (9.2%) (p < 0.001). Also, there was a significant difference in the frequency of use of liquid materials between JR-NET2 (21.2%) and JR-NET3 (41.2%) (p < 0.001). CONCLUSIONS: Embolization for feeders other than ECA and use of liquid materials could increase the complication rate in intracranial tumor embolization.

De novo vertebral artery dissecting aneurysm after internal trapping of the contralateral vertebral artery.

We present the case of a de novo vertebral artery dissecting aneurysm (VADA) after endovascular trapping of a ruptured VADA on the contralateral side. The first ruptured VADA involved the posterior inferior cerebellar artery, which was successfully treated by endovascular internal trapping using a stent. A follow-up study at 3 months revealed a de novo VADA on the contralateral side. The second VADA was successfully embolized using coils while normal arterial flow in the vertebral artery was preserved using a stent. Increased hemodynamic stress may cause the development of a de novo VADA on the contralateral side.

[Preoperative Embolization for Solid Cerebellar Hemangioblastoma on the Day of Surgery:Two Case Reports].

Surgical resection of solid cerebellar hemangioblastomas can be challenging because of the profuse blood supply and tight space. We report two cases of solid cerebellar hemangioblastomas treated via surgical resection with the aid of preoperative endovascular embolization on the day of surgery. Case 1: A 36-year-old woman presented with a two-month history of headache and vomiting. Magnetic resonance imaging(MRI)revealed a right cerebellar solid mass, mild hydrocephalus, and apparent peritumoral edema. Angiogram showed a highly vascularized mass, three feeding arteries from the superior cerebellar artery(SCA), and a dilated vein draining into the confluence. We performed preoperative embolization of the three feeders with 15% n-butyl-2-cyanoacrylate(NBCA). Final angiogram showed an absence of tumor staining. Tumor resection was performed on the same day, and gross total resection was achieved with no complications. Case 2: A 36-year-old man presented with a four-month history of headache and numbness in the left upper extremity. MRI revealed a right cerebellar solid mass with peritumoral edema. Angiogram showed a highly vascularized mass with two feeding arteries from the right SCA, one from the left posterior inferior cerebellar artery(PICA), and a dilated vein draining into the confluence. Preoperative embolization was performed with 15% NBCA, and complete devascularization was achieved. Tumor resection was performed on the same day, and gross total resection was achieved with no complications. In conclusion, preoperative embolization with NBCA on the day of surgery is a safe and effective adjunctive treatment for solid cerebellar hemangioblastoma.

Moyamoya Disease: A Review of Clinical Research.

About 5 decades have passed since the concept of moyamoya disease (MMD) was established in Japan. In that time, many clinical MMD studies have been performed from several different points of view, such as epidemiology, pathophysiology, surgical procedures, and prognosis. In addition, rapid developments in MMD genetic analysis have occurred. In light of all this activity, clinicians must continually update their knowledge of MMD in order to improve the prognosis of MMD patients. In this review article, we summarize the clinical MMD studies and introduce cutting-edge findings regarding MMD.